Network support of conventional end user services (e.g. telephony) of today are mostly monolithically packaged to be invoked from a user terminal from a service entity belonging to one service provider.
In a de-regulated market, which is the trend of today, the traditionally bundled, packaged network support of end-user services may be decomposed into constituting sub-components when the packaged services from a particular service provider are not used. Each of these constituting components may then be offered separately to the end-users by several different service providers, allowing the end-user to choose with whom to establish a business relation and thereby be allowed to invoke the individual service component. One service provider may also have many instances, service entities, of the same service component, e.g. geographically distributed. The end-user may also choose between the different service entities.
For example, in a multimedia conversation, individual service components, such as a conference unit, a transcoder, an encryption service, a multiplexer, etc. may be required and the end-user may invoke each of these from his terminal, as e.g. were they end-points in a conference.
Such a procedure would however have some drawbacks, e.g. result in a heavy signalling load, which in case of a cellular link has a high price in terms of spectrum cost. For a cellular operator, even savings in terms of single percentages counts, which is why signalling should be decreased if a cellular transport is used.
Furthermore, the terminal control logic complexity is increased in such a procedure, which also is a drawback.
The existing telecommunication networks, such as ISDN or GSM, use network based call control entity, not terminal based call control. In an IP-network, terminal based call control is an option.
Prior art methods exist which are meant to decrease signaling when invoking services. In the European Patent Application EP 0 762 789 A2, a network based agent performs complex signaling functions related to call processing on behalf of an associated mobile terminal, thus reducing the amount of signaling traffic that must travel over the valuable air interface.
Also agencies for establishing and maintaining desired Quality of Service (QoS) in wired systems are known. Such an architecture is described in the article “QoS Agency: An agent based Architecture for supporting Quality of service in Distributed Multimedia Systems” by L. A. Guedes et al, 1997 IEEE Conference on Protocols for Multimedia Systems-Multimedia Networking PROMS-MnNet (Cat. No 97TB100116) p. 204–12, ISBN 0818679166, 24-27 Nov. 1997.
An object of the invention is to give more freedom of choice for a terminal with respect to decisions about how services or service components implemented in a service entity, are controlled, e.g. how the terminal invokes services and service components and to realize this without a complex terminal control logic.
An object of the invention is also to decrease the overall signaling load in the network.